The present invention relates to small-sized equipment having a liquid crystal display (LCD) such as a radio telephone mounted on a motor vehicle and, more particularly, to small-sized equipment capable of switching over the visual angle of its LCD automatically.
An LCD has various advantages as well known in the art and are extensively used in a variety of fields today. Concerning the display surface of an LCD, the visual field angle remains substantially constant even when the visual angle to the display surface is changed. The visual angle, however, varies with the voltage which is applied to the LCD for driving it. When the small-sized equipment with an LCD is implemented as a desk-top portable word processor or similar apparatus, the visual angle of the LCD is not so critical. On the other hand, when it comes to a vehicle-mounted telephone or similar miniature equipment which is made up of a handset with an LCD and a cradle for mounting the handset thereof, the visual angle has to be considered with respect to the least two different conditions: a condition in which the handset is mounted on the cradle and a condition in which the handset is removed from the cradle by hand. Heretofore, this kind of consideration has not been reported at al. In fact, it has been customary to to provide even the equipment of the type which a person is incapable of seeing in one direction at all times with only single most effective visual angle which is expected under particular conditions of use.